The invention relates to a steamer arrangement comprising a cordless steaming device and a stand for holding the steaming device, said steaming device having a water tank and steam outlet ports, said stand having a water storage tank and electric heating means capable of receiving electric energy from an energy supply, said energy being used for heating said water storage tank, said steaming device and said stand being provided with mechanical coupling means including valves for coupling the water tank of the steaming device to the water storage tank of the stand for obtaining a fluid communication between the water storage tank of the stand and the water tank of the steaming device when the steaming device is attached to the stand.
Such an arrangement is known from U.S. Pat. No. 5,802,749. In most cordless irons available in the market, an electrical connection is only made between the iron and the stand for the purpose of supplying electric energy to a heating element provided in the iron for heating the soleplate. The latter then to accumulates an amount thermal energy when the iron is attached to the stand. The soleplate can be considered as a kind of accumulator. This enables the user to use the iron for a certain period of time without the iron being connected to the mains by means of a cord. In practice, however, the time for reheating the soleplate is too short, resulting in a too low soleplate temperature. The situation is even worse if the cordless iron is also suitable for steaming. To solve this problem, it is suggested in U.S. Pat. No. 5,802,749 to increase the energy transfer rate from the stand to the iron by accumulating an amount of energy in the stand and to transfer this accumulated energy to the iron when the iron is attached to the stand. It is suggested by way of example to heat liquid in the stand and to pump the heated liquid rapidly to the iron. The cooled-down liquid in the iron is pumped back to the stand for reheating. However, this kind of liquid transfer relies highly on the specific heat of the liquid, by which only relatively small quantities of energy can be stored and transferred. This limits the ironing and steaming capabilities of the cordless iron to a short period. It also requires the use of two sets of mechanical fluid couplings between the iron and the stand for fluid inlet and outlet, which presents difficulties for the user in terms of easy alignment during engagement and disengagement. Other examples, such as a flywheel and capacitors, appear to be impractical and require high-power electronics.
An object of the invention is to provide a steamer arrangement in which sufficient energy can be transferred from the stand to the cordless steaming device in order to have sufficient steam available during a usual operational in which a the user steams products continuously in each operation rest cycle, with the rest period utilized for steam charging.
The steamer arrangement according to the invention is characterized in that the water storage tank of the stand is provided with a steam space, said valves being opened when the steaming device is attached to the stand resulting in a steam flow from the water storage tank of the stand to the water tank of the steaming device, said water tank of the steaming device being provided with an outlet including a steam release valve which is connected to the steam outlet ports.
The invention makes use of a phase change between water and steam to transfer relatively large quantities of energy in terms of latent heat of vaporization, with a pressure difference as the driving force to transfer steam from the pressurized water storage tank of the stand to the water tank of the steaming device. This process is very rapid and efficient. When the steaming device is attached to the stand and the water storage tank is at a high pressure and temperature, high-pressure steam is transferred to the water tank of the steaming device. Since the temperature of the water tank of the steaming device is lower than that of the water storage tank of the stand, the steam partly condenses in the water tank until the pressures in both tanks are the same. After a short period of time the water tank of the steaming device is also pressurized and will contain water and steam under pressure, though not as high as in the water storage tank of the stand at the beginning of the transfer, but high enough to be used for steaming. The water storage tank may be heated during the steam transfer. When the steaming device is detached from the stand, electric power is supplied to the heater of the water storage tank to reheat the water. The cordless steaming device can be used for steaming the product through opening of the steam release valve.
In a preferred embodiment, the steaming device and the stand are provided with electric coupling means for transferring electric energy from the stand to the steaming device, and the steaming device is provided with electric heating means for heating water in the water tank of the steaming device when the steaming device is attached to the stand. The heating means may be, for example, an immersion heater inside the water tank or a heating element attached to or embedded in an outside wall of the water tank. Heating the water tank shortens the start-up period when the water in the water tank is relatively cold.
In another embodiment, the steaming device is provided with a hotplate and electric heating means for heating the hotplate when the steaming device is attached to the stand. Steaming devices are used for steaming objects which may sometimes have a vertical position, like curtains. A hotplate makes such a vertical ironing process easier. The hotplate touches the object only slightly during steaming. The steam outlet ports are preferably arranged in or around the hotplate, so that the steam flow is directed towards the object to be steamed. In this case, since the heat stored in the hot plate is not used for generating steam, the hotplate remains sufficiently hot for a long time.
In a further embodiment the hotplate is a soleplate of a steam iron.